前言:
目前大家对“sentinel持久化问题”大约比较珍视,同学们都想要分析一些“sentinel持久化问题”的相关文章。那么小编同时在网络上汇集了一些关于“sentinel持久化问题””的相关文章,希望看官们能喜欢,看官们一起来了解一下吧!本文实现基于拉模式的Alibaba Sentinel规则持久化。
一、拉模式架构
TIPS
图片来自官方。
引用自 在生产环境中使用-Sentinel
二、原理简述
•FileRefreshableDataSource 定时从指定文件中读取规则JSON文件(图中的本地文件),如果发现文件发生变化,就更新规则缓存。
•FileWritableDataSource 接收控制台规则推送,并根据配置,修改规则JSON文件(图中的本地文件)。
三、编写
修改Spring Cloud Alibaba微服务。
3.1 加依赖
<dependency> <groupId>com.alibaba.csp</groupId> <artifactId>sentinel-datasource-extension</artifactId></dependency>
3.2 写代码
/** * 拉模式规则持久化 * * @author itmuch.com */public class FileDataSourceInit implements InitFunc { @Override public void init() throws Exception { // TIPS: 如果你对这个路径不喜欢,可修改为你喜欢的路径 String ruleDir = System.getProperty("user.home") + "/sentinel/rules"; String flowRulePath = ruleDir + "/flow-rule.json"; String degradeRulePath = ruleDir + "/degrade-rule.json"; String systemRulePath = ruleDir + "/system-rule.json"; String authorityRulePath = ruleDir + "/authority-rule.json"; String paramFlowRulePath = ruleDir + "/param-flow-rule.json"; this.mkdirIfNotExits(ruleDir); this.createFileIfNotExits(flowRulePath); this.createFileIfNotExits(degradeRulePath); this.createFileIfNotExits(systemRulePath); this.createFileIfNotExits(authorityRulePath); this.createFileIfNotExits(paramFlowRulePath); // 流控规则 ReadableDataSource<String, List<FlowRule>> flowRuleRDS = new FileRefreshableDataSource<>( flowRulePath, flowRuleListParser ); // 将可读数据源注册至FlowRuleManager // 这样当规则文件发生变化时,就会更新规则到内存 FlowRuleManager.register2Property(flowRuleRDS.getProperty()); WritableDataSource<List<FlowRule>> flowRuleWDS = new FileWritableDataSource<>( flowRulePath, this::encodeJson ); // 将可写数据源注册至transport模块的WritableDataSourceRegistry中 // 这样收到控制台推送的规则时,Sentinel会先更新到内存,然后将规则写入到文件中 WritableDataSourceRegistry.registerFlowDataSource(flowRuleWDS); // 降级规则 ReadableDataSource<String, List<DegradeRule>> degradeRuleRDS = new FileRefreshableDataSource<>( degradeRulePath, degradeRuleListParser ); DegradeRuleManager.register2Property(degradeRuleRDS.getProperty()); WritableDataSource<List<DegradeRule>> degradeRuleWDS = new FileWritableDataSource<>( degradeRulePath, this::encodeJson ); WritableDataSourceRegistry.registerDegradeDataSource(degradeRuleWDS); // 系统规则 ReadableDataSource<String, List<SystemRule>> systemRuleRDS = new FileRefreshableDataSource<>( systemRulePath, systemRuleListParser ); SystemRuleManager.register2Property(systemRuleRDS.getProperty()); WritableDataSource<List<SystemRule>> systemRuleWDS = new FileWritableDataSource<>( systemRulePath, this::encodeJson ); WritableDataSourceRegistry.registerSystemDataSource(systemRuleWDS); // 授权规则 ReadableDataSource<String, List<AuthorityRule>> authorityRuleRDS = new FileRefreshableDataSource<>( flowRulePath, authorityRuleListParser ); AuthorityRuleManager.register2Property(authorityRuleRDS.getProperty()); WritableDataSource<List<AuthorityRule>> authorityRuleWDS = new FileWritableDataSource<>( authorityRulePath, this::encodeJson ); WritableDataSourceRegistry.registerAuthorityDataSource(authorityRuleWDS); // 热点参数规则 ReadableDataSource<String, List<ParamFlowRule>> paramFlowRuleRDS = new FileRefreshableDataSource<>( paramFlowRulePath, paramFlowRuleListParser ); ParamFlowRuleManager.register2Property(paramFlowRuleRDS.getProperty()); WritableDataSource<List<ParamFlowRule>> paramFlowRuleWDS = new FileWritableDataSource<>( paramFlowRulePath, this::encodeJson ); ModifyParamFlowRulesCommandHandler.setWritableDataSource(paramFlowRuleWDS); } private Converter<String, List<FlowRule>> flowRuleListParser = source -> JSON.parseObject( source, new TypeReference<List<FlowRule>>() { } ); private Converter<String, List<DegradeRule>> degradeRuleListParser = source -> JSON.parseObject( source, new TypeReference<List<DegradeRule>>() { } ); private Converter<String, List<SystemRule>> systemRuleListParser = source -> JSON.parseObject( source, new TypeReference<List<SystemRule>>() { } ); private Converter<String, List<AuthorityRule>> authorityRuleListParser = source -> JSON.parseObject( source, new TypeReference<List<AuthorityRule>>() { } ); private Converter<String, List<ParamFlowRule>> paramFlowRuleListParser = source -> JSON.parseObject( source, new TypeReference<List<ParamFlowRule>>() { } ); private void mkdirIfNotExits(String filePath) throws IOException { File file = new File(filePath); if (!file.exists()) { file.mkdirs(); } } private void createFileIfNotExits(String filePath) throws IOException { File file = new File(filePath); if (!file.exists()) { file.createNewFile(); } } private <T> String encodeJson(T t) { return JSON.toJSONString(t); }}
3.3 配置
在项目的 resources/META-INF/services 目录下创建文件,名为 com.alibaba.csp.sentinel.init.InitFunc ,内容为:
# 改成上面FileDataSourceInit的包名类名全路径即可。com.itmuch.contentcenter.FileDataSourceInit
四、优缺点分析
优点
•简单易懂
•没有多余依赖(比如配置中心、缓存等)
缺点
•由于规则是用 FileRefreshableDataSource 定时更新的,所以规则更新会有延迟。如果FileRefreshableDataSource定时时间过大,可能长时间延迟;如果FileRefreshableDataSource过小,又会影响性能;
•规则存储在本地文件,如果有一天需要迁移微服务,那么需要把规则文件一起迁移,否则规则会丢失。
五、你可能会有的疑问
Spring Cloud Alibaba不是提供了如下配置了吗?为什么要全部自己写呢?
spring.cloud.sentinel.datasource.ds1.file.file=classpath: degraderule.jsonspring.cloud.sentinel.datasource.ds1.file.rule-type=flow#spring.cloud.sentinel.datasource.ds1.file.file=classpath: flowrule.json#spring.cloud.sentinel.datasource.ds1.file.data-type=custom#spring.cloud.sentinel.datasource.ds1.file.converter-class=com.alibaba.cloud.examples.JsonFlowRuleListConverter#spring.cloud.sentinel.datasource.ds1.file.rule-type=flow
关于这个问题,可以看我提的Issue:[1]
六、参考文档
在生产环境中使用-Sentinel#pull模式
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References
[1]:
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